Centre for Public Health, Queen's University Belfast, Institute of Clinical Sciences B, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BJ, Northern Ireland, UK.
Department of Landscape Architecture and Environmental Planning, Natural Learning Initiative, College of Design, North Carolina State University, Raleigh, NC, 27607, USA.
Int J Behav Nutr Phys Act. 2021 Oct 30;18(1):142. doi: 10.1186/s12966-021-01213-9.
Evidence for the health benefits of urban green space tends to stem from small, short-term quasi-experimental or cross-sectional observational research, whilst evidence from intervention studies is sparse. The development of an urban greenway (9 km running along 3 rivers) in Northern Ireland provided the opportunity to conduct a natural experiment. This study investigated the public health impact of the urban greenway on a range of physical activity, health, wellbeing, social, and perceptions of the environment outcomes.
A repeated cross-sectional household survey of adult residents (aged ≥16 years) who lived ≤1-mile radius of the greenway (intervention sample) and > 1-mile radius of the greenway (control sample) was conducted pre (2010/2011) and 6-months post implementation (2016/2017). We assessed changes in outcomes pre- and post-intervention follow-up including physical activity behaviour (primary outcome measure: Global Physical Activity Questionnaire), quality of life, mental wellbeing, social capital and perceptions of the built environment. Linear regression was used to calculate the mean difference between post-intervention and baseline measures adjusting for age, season, education, car ownership and deprivation. Multi-level models were fitted using a random intercept at the super output area (smallest geographical unit) to account for clustering within areas. The analyses were stratified by distance from the greenway and deprivation. We assessed change in the social patterning of outcomes over time using an ordered logit to make model-based outcome predictions across strata.
The mean ages of intervention samples were 50.3 (SD 18.9) years at baseline (n = 1037) and 51.7 (SD 19.1) years at follow-up (n = 968). Post-intervention, 65% (adjusted OR 0.60, 95% CI 0.35 to 1.00) of residents who lived closest to the greenway (i.e., ≤400 m) and 60% (adjusted OR, 0.64 95% CI 0.41 to 0.99) who lived furthest from the greenway (i.e.,≥1200 m) met the physical activity guidelines - 68% of the intervention sample met the physical activity guidelines before the intervention. Residents in the most deprived quintiles had a similar reduction in physical activity behaviour as residents in less deprived quintiles. Quality of life at follow-up compared to baseline declined and this decline was significantly less than in the control area (adjusted differences in mean EQ5D: -11.0 (95% CI - 14.5 to - 7.4); - 30.5 (95% CI - 37.9 to - 23.2). Significant change in mental wellbeing was not observed despite improvements in some indicators of social capital. Positive perceptions of the local environment in relation to its attractiveness, traffic and safety increased.
Our findings illustrate the major challenge of evaluating complex urban interventions and the difficulty of capturing and measuring the network of potential variables that influence or hinder meaningful outcomes. The results indicate at this stage no intervention effect for improvements in population-level physical activity behaviour or mental wellbeing. However, they show some modest improvements for secondary outcomes including positive perceptions of the environment and social capital constructs. The public health impact of urban greenways may take a longer period of time to be realised and there is a need to improve evaluation methodology that captures the complex systems nature of urban regeneration.
城市绿地对健康的益处的证据往往来自于小型、短期的准实验或横断面观察性研究，而干预研究的证据则很少。北爱尔兰的一条城市绿道（沿着 3 条河流延伸 9 公里）的发展提供了进行自然实验的机会。本研究调查了城市绿道对一系列身体活动、健康、幸福感、社会和对环境的看法等结果的公共卫生影响。
对居住在绿道（干预组）和绿道（对照组）半径 1 英里以内的成年居民（年龄≥16 岁）进行了一次重复的横断面家庭调查。我们评估了干预后随访期间的结果变化，包括身体活动行为（主要结果测量：全球身体活动问卷）、生活质量、心理健康、社会资本和对建成环境的看法。线性回归用于计算干预后和基线测量之间的平均差异，调整年龄、季节、教育程度、汽车拥有量和贫困程度。使用超输出区（最小地理单元）的随机截距拟合多层次模型，以解释区域内的聚类。分析按与绿道的距离和贫困程度进行分层。我们使用有序逻辑回归来评估随时间变化的社会模式变化，以便在各层进行基于模型的结果预测。
干预组的平均年龄在基线时为 50.3（SD 18.9）岁（n=1037），随访时为 51.7（SD 19.1）岁（n=968）。干预后，居住在绿道附近的居民中，有 65%（调整后的 OR 0.60，95%CI 0.35 至 1.00），居住在绿道最远的居民中，有 60%（调整后的 OR，0.64 95%CI 0.41 至 0.99）符合身体活动指南-干预组中有 68%的居民在干预前符合身体活动指南。最贫困五分位数的居民的身体活动行为减少程度与较不贫困五分位数的居民相似。与基线相比，生活质量在随访时下降，且下降幅度明显小于对照组（调整后的平均 EQ5D 差异：-11.0（95%CI-14.5 至-7.4）；-30.5（95%CI-37.9 至-23.2）。尽管社会资本的一些指标有所改善，但心理健康方面没有观察到显著的变化。与吸引力、交通和安全相关的当地环境的积极看法有所增加。
我们的研究结果表明，评估复杂的城市干预措施具有重大挑战，并且难以捕捉和衡量影响或阻碍有意义结果的潜在变量网络。结果表明，在改善人群水平的身体活动行为或心理健康方面，现阶段没有干预效果。然而，它们显示出一些适度的改善，包括对环境和社会资本结构的积极看法。城市绿道的公共卫生影响可能需要更长的时间才能实现，需要改进评估方法，以捕捉城市再生的复杂系统性质。
